Process of making ferkous products



Jn. 23, 1934. P, A E ARMSTRONG Re. 19,058

PROCESS OF MAKING FERROUS PRODUCTS FACED WITH STABLE SURFACE ALLOYSOriginal Filed March 30 INVENTOR /g/y ,4r/77s rfofg BY Wl, M mi 0WATTORNEY Reissued Jan. 23,1934

UNITED STATES PATENT OFFICE PROCESS F MAKING FERROUS PRODUCTS' FACEDWITH STABLE SURFACE ALLOYS Percy A.. E. Armstrong, New York, N. Y.

4 Claims.

My invention is of a process for making ferrous products with weldedfaces of stable surface alloy material.

My present invention is a continuation in part I of my applicationSerial No. 63,975, filed October According to the present invention,ferrous metal is welded to a thin sheet of stable surface alloy bycasting the ferrous metal against such a thin sheet of stable surfacealloy, and by thereafter subjecting the resulting welded product to hotmechanical working, such as hot rolling, for example, with the ferroussurfaces in contact, a product is obtained with an inner portion offerrous metal and' outer surfaces of stable surface alloy on itsopposite sides.

In the accompanying drawing, I have illustrated a preferable mode ofcasting the ferrous material against and thereby welding it to a stablealloy material preparatory to the final step of hot mechanical working,as hot rolling, to produce the final product.

Fig. 1 is a plan view of an ingot mold with stable surface materialtherein, prior to casting.

Fig. 2 is a vertical section of the ingot mold during casting of theferrous metal; and

Fig. 3 is a section of the final rolled product.

In the showing selected Vfor illustration, two thin sheets 10, of stablesurface material are placed back to back, with preferably a layer ofasbestos 12 therebetween,.and same inserted in slots 14, 14, formingsubstantially central extensions of the ingot cavity`16 in the ingotmold .v

18. The slots 14, 14 not only will serve to hold the sheets upright inthe mold but will also serve to hold the sheets together so that whenmoltenmetal is poured around them, such molten metal will only contactwith the outside faces and not penetrate up between the sheets. This isa matter of particular importance in the case of stainless steels, fordue to the well-known quality of these steels of being slow to transmitheat, there is a great tendency for the sheets to warp when the moltenmetal is first poured against them, and this of course is particularlytrue when the sheets are made very thin as in the case of my invention.It is to be noted that in View fof the relative thickness of the sheets10, 10 as compared to the mold to be cast against them, preheating ofthese sheets is not essential.

Molten ferrous metal 20 when poured into the ingot mold at one side ofthe partition so formed passes in part through the hole 22 formed in thestable surface alloy sheets and the asbestos at preferably' the lowercentral portion thereof, so

that a part of the resulting ingot is top poured and the other part isbottom poured.. Such shrinking of the cast material as takes placeduring cooling tends to cause the ferrous metal to shrink upon andagainst the stable surface alloy sections arranged in the interior ofthe mold, and to avoid any effect of shrinking away therefrom.

The resulting ingot is separated into two parts on the parting planeproduced by the asbestos layer, and when hot rolled, with the sides 24,24 65 of the ferrous metal arranged in contact with one another and the'stable surface alloy faces looking outwardly and adapted for coming incontact with the roll surface, the ferrous metal is welded into asubstantially homogeneous interior portion, producing the final productshown in Fig. 3 and comprising the interior portion 26 of ferrous metal,having outer opposite face or surface portions 28, 28 of stable surfacealloy material. The faces 24, 24 of the ferrousmetal that are to be 75contacted may be machined smooth, or pickled before the compositeelement is subjected to hot rolling. This facilitates getting a goodweld. The ingot parts may be separately rolled or otherwise hot workedinto billet or bar form if desired, before being assembled in pairs asdescribed for the final hot rolling.

The ratio of the thickness of the cast backing material to the thicknessof the stable surface facing welded thereto in casting is to aconsiderable extent dependent upon the thickness desired for thefinished rolled-down product. In general, this ratio is less for theproduction of very thin sheets than for the production of thickersheets, since with the former a larger proportion of the sheet thicknessmust be made up of the stable surface layers in order to preventexposure of the backing in the course of working, drawing, etc., for theproduction of articles, particularly cupped articles, therefrom, and'inthe ordinary 95 uses and wear to which the articles are subjected. Withthicker sheets relatively more of the crosssection may be made up of thebacking material without danger of exposure of the backing material inthe event of slight mechanical wear.

The cross-sectional area of the cast metal is preferably more than threetimes, and more preferably over ve times, the cross-sectional area ofthe solid sheet against which same is cast. With a ratio of cast backingmaterial to the solid plate of surfacing material which is materiallyunder 3:1, the weld is generally poor and unduly high temperatures haveto be used for the molten metal, which may result in porous .ingots,ingot cracks and heavy shrinkage. With the produc-f tion of relativelythicker finished products the ratio above referred to may beadvantageously 5: 1 or higher, and with such relation between the castmetal and the solid metal sheet inserted in the ingot mold, good weldscan be produced without the use of unduly high heat for the moltenmaterial.

Various stable surface alloys may be used, as for example so-calledrustless steel or iron with about 7-30% of chromium and with variousother alloying materials. The choice of ferrous material to be castagainst and Welded to the sheets of stable surfacing material willdepend upon requirements, but for general purposes carbon steel of .05%to 1% of carbon gives good results.

The rolled metal faced with welded surfaces of stable surface alloy canbe used for various products and articles of which a few are, forexample, sheets, roongs, conductor pipe conduits, shingles, cookingutensils, containers for foodstuffs, and articles for taking the placeof tinware, zincware and plated-articles generally.

I claim:

1. Process of making sheets of ferrous metal faced on opposite surfaceswith stable surface alloy which consists in casting ferrous metalagainst solid stable surface alloy material in relatively thn sectionssuch that the thickness of the alloy is not more than one-third thethickness of the ferrous metal cast against it, and subjecting theresulting welded product to hot mechanical working in pairs with theferrous surfaces arranged in contact and the stable surfaces facesdirected outwardly.

2. Process of making sheets of ferrous metal faced on opposite surfaceswith welded surface portions of stable surface alloy, which comprisesarranging relatively thin sections of solid stable surface materialbackto back in an ingot mold;

casting ferrous metal between the insert and the mold walls, separatingthe resulting ingot parts, each comprising a ferrous metal part and astable surface alloy part welded thereto in casting, and reversing sameto bring the ferrous surfaces into contact and the stable surface alloyfacing outwardly-on opposite sides, and subjecting to hot mechanicalwork, as by hot rolling, whereby the ferrous metal part is Welded into ahomogeneous interior portion and s'ame is faced on its opposite sideswith welded thin surface portions of stable surface alloy material.

3. The method of making faced metal sheets which comprises preparing twothin sheets of a stable surface ferrous alloy, putting separatingmaterial between the sheets, positioning the sheets in an ingot mold andpositively holding the sheets together so as to prevent the ingress ofmolten metal between them, casting ferrous metal around such sheets of athickness of at least about three times the thickness of such sheets,permitting such cast metal to shrink around and against the sheets,whereby an ingot is formed adapted to be separated into two parts, andthereafter separating and hot Working such ingot parts.

4. The process of making sheets of ferrous metal faced with stablesurface alloy which com' prises preparing two sheets of stable surfacealloy, positioning them in a mold with a separating material betweenthem, positively holding the edges of such sheets together and castingferrous metal on both sides thereof simultaneously, with the metal onboth sides interconnected so that the cast metal on cooling will shrinkupon and against the stable surface alloy sheets, whereby an ingot isformed adapted to be separated into two parts, and thereafter submittingsuch ingot parts to the` operations of separation and hot working.

PERCY A. E. ARMSTRONG.

IUI)

